Nomenclature
CAS number: 10026-12-7
Niobium chloride (NbCl
5); columbium pentachloride; niobium(V) chloride.
Cl
5Nb; mol wt 270.17.
Cl 65.61%, Nb 34.39%.
NbCl
5.
Description and references
Exists as dimeric units in the solid state.
Prepn: Epperson et al., Inorg.
Synth. 7, 163 (1963); cf. Rolsten, J. Am. Chem. Soc. 80, 2952 (1958).
Toxicity studies: T. J. Haley et al., Toxicol. Appl. Pharmacol. 4, 385
(1962); N. A. Zhilova, A. A. Kasparov, Hyg.
Sanit. 31, 328 (1966). Review of niobium halides:
Fairbrother in Halogen Chemistry Vol. 3, V. Gutmann, Ed. (Academic Press, New York, 1967)
pp 123-178. Review of applications in organic synthesis: C. K. Z.
Andrade, Curr. Org. Synth. 1, 333-353 (2004).
Properties
Yellow, very deliquesc, monoclinic crystals; dec
in moist air with evolution of HCl. d 2.75. mp 204.7-209.5°; bp ≈250°,
but begins to sublime at 125°. Sol in HCl, carbon tetrachloride.
LD50 in mice (mg/kg): 61 i.p., 940 orally (Haley). LD50 in mice, rats
(mg/kg): 829, 1400 orally (Zhilova, Kasparov).Use
Lewis acid catalyst in organic synthesis.